1. Field of the Invention
The present invention relates to an inductive component with variable magnetic performance, wherein an electric current is conducted through a winding and a magnetic field is generated in a magnetic core by the current flowing through the winding.
2. Description of the Related Art
It is known that the inductance of inductive components can be adapted, or in other words adjusted to a desired value after assembly, by mechanical or magnetic means. There are described, in "Ferritkerne - Grundlagen, Dimensionierung, Anwendungen in der Nachrichtentechnik" Ferrite Cores-Fundamentals, Dimensioning, and Communications Applications! by S. Kampczyk and E. Rob, 1978, Siemens AG, pp. 266-268, variometers in which (similarly to the case of a rotary capacitor) the inductance can be adjusted continuously during operation to whatever value is desired. In such variometers, the inductance can be varied by factors by means of a magnetic field. It this kind of electromagnetic adaptation, the magnetic core of the inductive component is more or less premagnetized by means of a variable direct current flowing in an auxiliary winding. That is, this makes use of the phenomenon that the alternating field permeability (superposition permeability or reversible permeability) becomes less the greater the premagnetizing direct field.
Similar conditions prevail in the case of transductors, which are known for instance from "Enzyklopadie Naturwissenschaft und Technik" Encyclopedia of Natural Sciences and Technology!, 1961, Verlag Moderne Industrie, p. 4586. Those devices are controllable choke coils with nonlinear magnetic properties, which can be used in magnetic amplifiers, regulators, limiters, actuators, switches and converters. The fundamental element is a choke coil with at least one magnetic core, which contains in addition to the working winding at least one control winding as well. Once again, the properties of the transductor choke depend on the magnetization characteristic curve, whose nonlinearities are exploited. By magnetic saturation of the core material, an inductance of the working coil is obtained that is dependent on the magnetic flux. The magnetic flux is influenced not only by the current in the working windings but also via the current in the control windings.